Automatic infeed mechanism for grinding machines



J. DECKER May 13, 1941.

AUTOMATIC INFEED MECHANISM FOR GRINDING MACHINES 4 Sheets-Sheet 1 FiledApril 12, 1940 INVENTOR. JYcofi Die m? ATTORNEY.

I MN 93 w R N \N l R E 2 Q. n 4 m N S k M 39 $233.53; MN 1 iiaxli at .H,.3 AN .GNHNW J. DECKER May 13, 1941.

AUTOMATIC INFEED. MECHANISM FOR GRINDING MACHINES Filed April 12, 1940 4Sheets-Sheet 2 INVENTOR. JF/toa flfcmw WWW A TTORNEY.

J. DECKER May 13, 1941.

Filed April 12, 1940 4 Sheets-Sheet 4 HH HI HIHH H H F .0 H H hHl F RVM5 0 No sh; .8 a R km l a 6% l a F raw: O m AT .w \NM m m5 M A. Y u. .v8 M0 bb. L Q? F R? 5: Mm. 3 Vk a Q. W Q9 MIN v Mn 3% M\\ 4... 0 ,1 QR 4wmm v Q H ,1 z \\\\M\F M an n Patented May 13, 1941 is? i ATENT.iKITOMATIG INFEEE ems Jacob Decker, Cincinnati, Ohio, assignor to cmcinnati Grinders Incorporated, Cincinnati, Ohio, a corporation of OhioApplication April 12, 1940, Serial No. 329,333

12 Claim.

This invention relates to grinding machines and more particularly toautomatic cycle control mechanism therefor.

nism which is simple and rugged in construction and positive inoperation.

A further object of this invention is to provide an improved mechanicalmechanism for infeeding a grinding wheel support which is poweredhydraulically whereby the positive features of mechanical operation andthe advantages hydraulic control may be obtained in a single structure.

Other objects and advantages of the present invention should be readilyapparent by reference to the following specification, considered inconjunction with the accompanying drawings forming a part thereof and itis to be understood that any modifications may be made in the exactstructural details there shown and described, within the scope of theappended claims, without departing from or exceeding the spirit of theinvention.

Referring to the drawings inwhich lifie reference numerals indicate likeor similar parts:

Figure 1 is an elevational view partly in section of a machine embodyingthe principles of this invention. 7

Figure 2 is an enlarged detail section on. the line 2-4 of Figure 1.

Figure 3 is a section on the line 8-3 of Figure 2.

Figure 4 is a section on the line Q4 of Figure 3.

Figure 5 is a diagrammatic view of the hydraulic control circuit.

Referring to Figure 1 of the drawings the reference numeral Illindicates in, general the bed of the machine, and the reference numeralH in- .dicates the work support which is slidably supported by the flatand. V guides l2 and 63 respectively formed on the bed. A grinding wheelH is rotatably mounted on a grinding wheel support or slide I5 which isrelatively movable with respect to a sub-support l6 toward and from thework support II. The grinding wheel It may be powered in a conventionalmanner by an electric motor I! carried by the support l5.

This invention deals with an-hnproved automatic infeed cycle controlmechanism. for effecting plunge cut grinding operations on surfaceswhose axial length is less than the width of the grinding wheel face. Inview of this, no mechanism has been shown for traversing the table sincesuch mechanism forms no part of the present invention but it will beunderstood that any suitable traversing mechanism may be employed forthat purpose.

The final driving elements of the inieeding mechanism of this inventionconsist of a rack it which, as shown in Figure 1 is integral with. theslide l5. and a pinion it supported in engagement with the rack by ashaft 28, the shaft passing centrally through the support it whereby thesubsupport i6 may be rotatably adjusted about the axis of the shaft 2|!to vary the plane of rotation of the grinding wheel.

Referring to Figure 2, the shaft 2% has a gear 2! keyedthereto in aposition to intermesh with rack teeth 22 formed on the side of anelongated piston 23 slidably mounted in a cylinder A set screw 25engages a longitudinally extending groove 2e formed in the piston forpreventing rotation thereof and maintaining the rack teeth being mountedin a housing 29.

in proper mesh with the gear 25. The piston it constitutes a fluidoperable member for shifting the grinding wheel support at a rapidtraverse rate as well as at a feed rate, there being addi tionalmechanism provided for controlling the rate of feed as will be describedhereeitsr.

This additional. mechanism includes a worm wheel 21 and an intermeshingworm fit, the worm The worm is has integral reduced bearing portions 3%and hi projecting axially from opposite ends thereof, which aresupported by anti-friction needle been ings 32 in sleeves 33 and 3d. Thesleeves arse held against rotation by set screws 35 winch engagelongitudinally extending slots 33$ out in the periphery of the sleeves.Although the bearing portions rotate relative to the sleeves, washers 31are provided on the bearing portions so that the worm andsleeves move asa unit in the bore 38 of the housing. This bore is provided with endstops 39 and 40 which engage the ends of the sleeves to define theamount of social movement of the worm.

Since the worm. wheel 27 is keyed to the shaft 20 for movement therebyit will be apparent that these and stops define the amount of movementthat can be imparted to the wheel slide by the piston 23.

The end stop 39 determines the return position of the wheel slide whichis also the starting p0- sition for an automatic inieed cycle. Thisposition may be varied, however, relative to the worm by rotating theworm through the shaft ii which has a telescoping spline connection withthe shaft H which, as shown in Figure l, is provided with a gear 42which intermeshes with a pinion 48 mounted on the end of amanually'rotatable shaft 44. This shaft extends to the front of themachine and is provided with a hand wheel 45 as well as a pick feedwheel 48. By rotating the hand wheel 45, the worm wheel 21 may berotated without changing the axial position of the worm whereby thegrinding wheel slide and the piston 28 are caused to take up a newreturn position. Therefore, the cylinder 24 is made sufilciently long toaccommodate all the positions which the grinding wheel slide might have.-When the wheel slide is in a return position hydraulic pressure isalways connected to the left end of cylinder 24 whereby the worm wheel28 is held against positive stop 88, thereby preventing axial movementof the worm during rotation thereof to effect movement of the wheelslide. It will thus be apparent that the hand wheel 45 changes the zoneof movement of the piston 23.

An automatic cycle is initiated by moving the valve plunger 41 of thecycle control valve 48 to the left as viewed in Figure 5. This valve hastwo pressure ports 48 and 58 which are connected by a common channel 5ito a pump 52 which has an intake 58 through which fluid is drawn from areservoir 54. The channel 5i has a branch 55 leading to pressure port 58of the feed control valve 51.

In the stop position the valve plunger 58 is to the right whereby theannular groove 58 interconnects port 58 to port 58' and thereby tochannel 88 which leads to port 8I located in the left hand end of thecycle control valve 48. It will thus be "apparent that fluid pressureentering opposite ends of the valve casing 48 through ports 58 and-5Iacts on opposite ends of the valve plunger but since the area 82 of theleft end of the plunger is larger than the area 83 there is adifferential which holds the plunger in its right hand position definedby the detent 84. Thus, when the operator throws the starting lever 85he must overcome this differential pressure in order to throw the valveplunger in a running position. when this has been accomplished, the port48 is connected by the annular groove 88 to port 81 whereby fluid flowsthrough branch channels 88 and 88 which are connected through a commonchannel 18 to port The channel 88 terminates in a port 1| located in theright hand end of the cylinder 24 causing movement of piston 23 to theleft whereby the wheel slide will advance at a relatively rapid rate. Atthe sametime the port 12 located in the left end of cylinder 24 isconnected to reservoir through channel 18, interconnected ports 14 and15 of the cycle control valve 48 and channel 18 which leads to thereservoir 54.

The branch channel 88 terminates in ports 11 and 18 of a main pilotvalve 18 and port 88 of an auxiliary pilot valve 8i. The main pilotvalve 18 has a valve plunger 82 which is held in its right hand positionas shown in Figure 5 by a spring 83. In this position an annular groove84 formed in the plunger 82 interconnects port 11 with port 85 wherebythe pressure fluid continues through channel 86 to port 81 located inthe right hand end of the auxiliary pilot valve 8i. This causes ashiftin'gof the auxiliary pilot valve plunger 88 to the left. againstthe compression of a spring 88 whereby the pressure port 88 isinterconnected by the annular groove 88 to port 8i causing fluid to nowthrough channel 82 to port 88 located in the right hand end of the feedcontrol valve housing 51. By" this time the piston 23 has completed therapid traverse movement of the wheel slide and the worm 28 has beenshifted axially by rotation of the worm wheel 21 until the-end of thebearing portion 8i abuts the end of a follower 84 of a cam 85. Thispositively stops the rapid movement of the wheel slide. 1

- The cam 85, as shown in Figure 3, is keyed to the upper end of arotatable shaft 88 which is supported for rotation. in a. housing 81.The

cam 85 has a receding peripheral surface 88' whereby upon rotation in acounterclockwise direction it will permit further advance of the worm 28toward the right under the pressure of the fluid in the right hand endof cylinder 24 acting This piston is slidably mounted in a cylinder II82 which has ports I88 and I84 located at opposite ends thereof. Theport I88 is connected by a channel I85 to port I88 of the feed controlvalve 51. An adjustable throttle valve I81 is serially arranged'in thischannel for varying the feed rate. A check valve I88 is connected inparallel across the throttle valve, and so positioned as to stop flowto'the feed piston while permitting return flow therefrom.

when the plunger 58 of the feed control valve 51 is shifted'to the leftby fluid pressure entering port 88 the port I88 is connected by theannular groove I88 to pressure port 58. This will cause fluid to enterthe feed cylinder I 82 at a rate de- .termined by the setting of thethrottle valve I81 and cause rotation of the cam 88 to produce a slowrate of advancing movement of the grinding wheel slide. The recedingsurface 88 is of such contour thatby the time the piston I8I- hasreached the end of its cylinder it willhave moved out of engagement withthe follower 84 due to 'the fact that in the meantime the worm 28 hashit the positive stop 48. It will thus be apparent that although the camacts to control the feed rate it does not act as a positive stop fordetermining the final infeed position of the grinding wheel slide. I

It will be obvious that during rotation of the cam 85, its supportingshaft 88 to which it is keyed will also be rotated, and this shaft isprovided with a pinion portion I I8 which is engaged engage the end ofthe main pilot valve plunger 82.

This will shift the plunger against the compression of spring 83 untilthe annular groove to areservoir port III. The result of this is thatthe fluid which shifted the feed control .valve plunger is now exhaustedto reservoir, and

pump pressure is connected through port Ill and an adjustable throttleor delay valve II8 position.

to port m of valve housing 51 tending to um:

the plunger 58 to theright. It will thus be obvious that while theplunger 58 is slowly moving to the right, that the grinding wheel slidehas advanced the full length of its movement and is gradually sparkingout.

t The length of time that the grinding wheel will be finishing thesurface will depend upon the setting ofthe delay valve III. When the'valve plunger 58 has completedv substantially one -half of itsmovement, or in other words as soonas the valve spool Ill cracks theport fluid pressure will flow to port 59' and branch 'IIS to theauxiliary cylinder I20 located in the left hand end of the valve housing51 so that pressure will act on the end I2I of theplunger 53 moreeffectively and the further the plunger 53 moves to the' right thefaster will the fluid pressurerun into the chamberl20 whereby theplunger 58 becomes self-actuating tocomplete the last half of itsshifting movement.

.When the plunger 58 has returned, the pressure fluid now being admittedto channel 60 through port 59 will enter port SI of the starting valveand shift plunger 41 to the right:

The fluid entering the left end of the housing .33 will continue throughport I22 after it has been uncovered and channel I23 to port I of thefeed cylinder I02. Shifting of the plunger 41 will also reverse theconnections to cylinder 24, port 1I now being connected to reservoirversely varying the length of the rapid traverse stroke and the feedstroke, it being remembered through port I24 and port 12 being connectedto pressure through the interconnectionof ports l3 and 14. Thus, thepiston 23 and the feed piston IIJI will rapidly return to their startingpositions.

Since the amount of excess stock on work coming to a grinding machinehasa wide variation, provision is made for varying thelength of the feedstroke so that the-machine may be oper'ated efliciently'at all times.scribed, the feed controlcam has 'a receding surface which means thatthe radius of the periphery gradually reduces from the radial line I26,

I which is coincident with the axis of the follower when the feedpiston. IOI is in its maximum return position, to the radial line I26which is coincident with the axis of the follower when the feed pistonis in its maximum advanced Therefore, if the feed piston is not toreturn to its maximum return position but some distance short of thatposition, the length of the particular cam radius which is coincidentwith the axis of the follower will be less than the radius I25, whichmeans that the rapid traverse movement of the wheel slide will begreater, and therefore the grinding wheel will approach the work agreater distance before its rate of movement is changed to a feedingrate. Means are, therefore, provided for varying the return position ofthe feed piston thereby of the cam 98 whereby the length of the rapidtraverse movement-may be increased and the length of the feed movementcorrespondingly permitted v .40 As previously de- King an intermeshingworm and worm gear,'

, able means forrotating said worm to adj IIII and that the sum of thesetwo distances must always be equal to the total movement permitted bythe positive stops 33 and 40 for the worm 28, is moreparticularly shownin Figure 4.

This mechanism comprising a rack plunger I21 which is slidably guided ina bore I23 of the housing 9.1 and in intermeshing relation with I30connects this threaded stop through gearing I I3I, to a manuallyadjustable dial I32 located on the front of the machine as shown inFigure 1. This dial may be suitably graduated to indicate the length offeed movement which should approximate the amount of excess stock to beremoved from awork piece. Thus, by means oi. this mechanism the startingposition of the cam may be varied and by such variation the relativelengths of the rapid movement and the feed movement are inverselychanged.

Attention is invited to the fact that the starting valve 48 is in effecta reversing valve for the rapid traverse piston and a control valve forone end of the feed piston. In other words, it controls the admission offluid pressure to effect the return stroke of the feed piston, but sincethe port I22 is closed during the advance of the feed piston a checkvalve I33 is so connected to channels I23 and 60 as to by-pass exhaustfluid around the closed port. An additional check valve I34 is providedin parallel with the throttle ord'elay valve-I I6 to permit exhaust offluid to reservoir through port II 1 of the feed control valve when theplunger 58 is shifted to the left to start thetfeeding movement.

There has thus been provided an improved infeed control mechanism for agrinding machine which is simple and rugged in construction, easy toadjust, and efiicient in operation.

What is claimed is:

1. In a. grinding machine having a work .support anda grinding wheelsupport, the combination of an infeeding mechanism therefor includmotiontransmitting means connecting the worm gear to the movable support, amanually,operuist the support through the worm gear, a fluid operablepiston for shifting the movable support at a rapid 7 rate whereby saidworm is shifted axially by reaction of the worm gear thereon, a-cam forlimiting the extent of axial movement of said worm, and means to actuatesaid cam to produce additional-movement of the support by the piston ata feeding rate under control of said cam.

decreased in accordance with the stock removal requirements of a givenwork piece.

The total fall in the arcuate periphery of the cam between the radii I25and I26 represents, of course, the maximum length of feeding move-.ment, and has been determined'to take care of the maximum requirementsofthe machine, and the means referred to above have been provided forreducing the fall in accordance with particular requirements. Themechanism for in- 2. In a grinding machine having a work support and agrinding wheel support, the combina tion of means for effecting relativemovement between the supports including a power operable member, motiontransmitting means connecting the memberfor. movementcfone of saidsupports at a rapid rate, a feed control cam, a part shiftable jointlywith the support into abutting engagement with said cam for stoppingsaid rapid movement, means to actuate said cam to permit furthermovement of said. part and thereby of said support at a feed rate, apositive stop, said cam having a receding profile of such extent thatthe cam will eventually move out of engagement with saidpart wherebysaid positive stop will determine the final infeed position, of saidsupport.

3. In a grinding machine having a work support and a grinding wheelsupport, the combination of means for effecting a relative infe'edingmovement of the grinding wheel support including a first power operablemember for effecting a rapid advance movement oi. said support, meansfor positively stopping said advance movement including a cam. and apart movable with said support and engageable with said cam, a secondpower operable member for actuating said cam, said cam having a recedingsurface to permit further advance of said support at a feed rate, and afinal positive stop effective independently of said cam for determiningthe final infeed position of said support.

d. In a grinding machine having a work support and a grinding wheelsupport, the combination of an infeeding mechanism including poweroperable means for effecting a rapid advance oi the grinding wheelsupport, means subsequently operable for producing a feeding movementincluding an inieed control cam, a cam i'ollower movable with thesupport into engagement with said cam, a fluid operable piston foractuating the cam to produce a feeding movement, means trip operable bythe piston for reversing its direction 01' movement, and adjustablemeans ior determining the extent of the return movement of the pistonand thereby the starting position of said cam.

5. In a grinding machine having a work support and a grinding wheelsupport. the combination of an infeeding mechanism including poweroperable means for effecting a rapid advance oi the grinding wheelsupport, means subsequently operable for producing a feeding movementincluding an inteed control cam, a cam follower, movable with thesupport for engaging said cam and stopping the rapid movement, a iiuidoperable piston for actuating the-cam to produce the feeding movement,means trip operable by the piston for reversing its direction ofmovement, and adjustable means for determining the extent of said returnmovement and thereby the starting position of said cam, said adjustablemeans including a threaded stop and a plunger movable in synchronismwith the piston for engagement with said stop.

6. In a grinding machine having a work support and a grinding wheelsupport, the combination of means for moving one of said supports towardand from the other including a worm wheel and a rotatable axiallymovable worm, a housing supporting said worm and having positive stopsat each end for determining the extent of axial movement of said wormand thereby the extent of movement of said support for either rotationor axial shifting of the Worm, power operable means for effecting partof said, axial movement at a rapid rate, and additional means forcausing the rest of said movement to tnlse place at a feed rate. r

7. In a grinding machine having a work support and a grinding wheelsupport, the combination of a hydraulic control circuit for efiecting arelative infeeding movement between said supports including a rapidtraverse piston, a feed piston, a source of pressure, a starting valvefor connecting fluid pressure to said rapid traverse piston, a feedcontrol valve, a pilot valve and an auxiliary pilot valve, meansoperable by the starting valve for connecting fluid pressure to saidpilot valves, means in the main pilot valve to efiect hydraulic shiftingof the auxiliary pilot valve and thereby eiIect a connection of shiftingpressure to the feed control valve, means operable by the feed controlvalve for connecting pressure to said feed piston, and means operable bythe feed piston for shifting said main pilot valve to cause returnmovement of both of said pistons.

8. In a-grinding machine having a work support and a grinding wheelsupport and means intervening said supports permitting a relativemovement in a direction toward and from each other, of means foreflecting said relative movement including a first actuating pistonhaving an extended axial movement, a second member having a limitedaxial movement, means inter connecting said axially movable elements,whereby the member having limited movement determines the extent ofmovement oi the piston, and means ifor varying the phase relationship 01said parts whereby the potential zone of axial movement of the piston isvaried, and additional means interconnecting the piston and one of thesupports for efiecting movement of the support in accordance with andthrough the selected zone of activity of the piston.

9. In a grinding machine having a work support and a grinding wheelsupport and means intervening said supports permitting a relativemovement in a direction toward and from each other, of means foreffecting said relative movement including a. first actuating pistonhaving an extended axial movement, a second member having a. limitedaxial movement, means interconnecting said axially movable elements,whereby the member having limited movement determines the extent ofmovement of the piston, and means for varying the phase relationship ofsaid parts whereby the potential zone of axial movement or the piston isvaried, additional means interconnecting the piston and one o! thesupports for effecting movement of the support in accordance with andthrough the selected zone of activity or the piston, a shittableabutment having a portion projecting to engage the axially movablemember, and an additional piston mechanism reacting on the abutment forvariably determining the positioning thereof and thus the rate ofmovement of the shiftable support.

10. In a grinding machine having a work support and a grinding wheelsupport and means intervening said supports permitting a relativemovement in a direction toward and from each other, 0! means foreffecting said relative movement including a first actuating pistonhaving an extended axial movement, a second member having a limitedaxial movement, means interconnecting said axially movable elements,whereby the member having limited movement determines the extent ofmovement of the piston, and means for varying the phase relationship oi!said parts whereby the potential zone of axial movement of the piston isvaried, additional means interconnecting the piston and one of thesupports for eflecting movement of the support in accordance with andthrough the selected zone of activity of the piston, a shiftableabutment having a portion projecting to engage the axially movablemember, an additional piston mechanism reacting on the abutment torvariably determining tional means for variably determining the limit ofmovement of the second piston and thus the ultimate position of theabutment controlled theicby.

11. In a machine of the character described, the combination with a pairof relatively adjustable supports, of means for effecting relative rapidtraverse feed movements thereof including a drive shaft, a hydraulicmotor for effecting rotation of .the shaft, a driving connection fromthe shaft to the movable support, and means for determining theextentand rate of rotation of the shaft including a worm wheel carried by theshaft, a worm housing in fixed relation to one of the supports, a wormrotatably and translatably mounted in the housing, means for rotatingthe worm to effect through the worm gear rotary adjustment of the shaftand coupled hydraulic motor and thus the position of the movablesupport, a first means for limiting the axial movement orthe worm, avariable positionable abutment proiectable into the path of movement ofthe worm, and means including a variable speed hydraulic motor coupledwith the abutment for determination of the positioning thereof, wherebysaid latter motor by reaction on the worm determines the rate of feedingmovement of the shiftable support. a

of the supports, a worm rotatably and trans latably mounted in thehousing, means for rotating the worm to effect through the worm gearrotary adjustment of the shaft and coupled hydraulic motor and thus theposition of the movable support, a first means for limiting the axialmovement of the worm, a variable positionable abutment projectable intothe path of movement of the worm, means including a variable speedhydraulic motor coupled with the abutment for determination of thepositioning thereof, whereby' said latter motor by reaction on the wormdetermines the rate of feeding movement of the shiftable support, andmeans for variably limiting the extent of movement of the abutmentcontrolling motor and thus the ultimate positionin of the worm andsupport. a Y

JACOB DECKER.

